The effects of local micro injections of opiates and enkephalins into the forebrain on the electrocorticogram of the rat

Effect of Opiates on the Caudate Spindle in the Cat

“…The caudate nucleus has also been suggested to be a key brain structure involved in the mechanisms of opiate dependence, hyperalgesia and change of behavioural patterns [7]. It has been reported that intracaudal administra tion of opiates produced synchronization in the elcctrocorticogram (ECoG) in the rat [14], The result is very similar to that observed fol lowing systemic administration of opiates. It is possible, that the head of caudate nucleus constitutes the site of action of systemically and intracerebrally administered opiates, be cause this region is very rich in opiate recep tors [12].…”

“…It has been re ported that an injection of dopamine into the head of the caudate nucleus enhanced both spontaneous and stimulation-evoked spin dling [10]. It is therefore possible that the observed facilitation of caudate spindling fol lowing local administration of opiates is due to the stimulation of opiate receptors inter acting with the dopaminergic system [8,10,14].…”

Naloxone Injected into the Preoptic Region Has Hypophysiotropic and Seizurogenic Actions in Rats.

“…of the site occupied by cholinergic neurons enhances the neocortical and hippocampal neuronal activity [30][31][32][33][34], it is probable that naloxone somehow causes the activation of these cholinergic neurons. There is a report that microinjection of opiate and opioid in the forebrain produces EEG slow waves and spindling in rats [35], suggesting that naloxone injected there may antagonize this opioid inhibition upon the cholinergic neurons. In addition, there is agreement that the seizurogenic action of naloxone is a result of GABA receptor blockade [23,24,36,37], and thus this GABA antagonism, too, is able to cause disinhibition of cholinergic neurons.…”

Drug Effects on Sleep-Wakefulness Patterns in Dogs

“…While in mice and cats, morphine-like agents produce excitation, in nonaddicted rats [Neal and Keane, 1978], rabbit [Gangloff and Monnier, 1955] and dog e] EEG synchronization is seen, a state which might be termed 'narcotic hypnotic' and which is associ ated with analgesia and behavioral depression. Such ef fects were not only seen following systemic administra tion, but also following intracerebral application [Tortella et al, 1978].…”